Several Soft Focus lenses compared

[djdister]

I think I like the Wollaston the most, of the three lenses compared.

[Adamphotoman]

Arrival of my Wollaston last week started the comparison.
I agree with Dan
Good thing that these are readily available from Reinhold.

[Old-N-Feeble]

RE Imagon discs: I don't like them. I'll only use the shutter's built-in aperture. Those Imagon "strainer" discs completely destroy bokeh, IMHO. I'll never understand why the discs were made that way. Otherwise the Imagon is a beautiful portrait lens.

[Mark Sawyer]

Mark, your astigmatism comment doesn't make sense, unless you have an improperly ground lens. Explain, please.

Astigmatism is one of the seven deadly sins, I mean seven primary aberrations, in lenses. It causes lenses to be slightly sharper on one axis than on the perpendicular axis. The Zeiss Anastigmat/Protar of 1890 was the first anastigmat, so any design that pre-dates it has astigmatism to some degree. I just thought I saw a lot more than is usually noticeable, but Jac@stafford.net could be right...

Mark, could this be due to the requirement to have stronger contrast in the lighting? The light intensity is dropping in the 2-8 position. Just wondering.

That could be too... never try to analyze a lens after a couple of late night martinis!

[mdarnton]

Astigmatism should be rendered concentrically, not linear in a particular line. That is, both legs of an X won't be simultaneously in focus, and both arms of a + wouldn't either, with the same lens. If the lens is made spherically, there shouldn't be a particular axis for this--it's simply relative, that any two lines perpendicular to each other can't be in focus at the same time.

[Adamphotoman]

I have to say that I am not yet a fan of the Imagon strainer, but I will give myself a chance to learn how to use it.

[Mark Sawyer]

Here's an example of the astigmatism I was referring to. One axis in focus, one not:

[mdarnton]

Now turn that target 45 degrees, so that the angle is between that example, focus on the lines going in one direction and see how the others look. Or for that matter, set up the same target and focus on the other set. No matter what the orientation, one pair should be in focus, the other not, and you should be able to choose which one to focus on.

[goamules]

I can't turn it! I CAN'T turn IT! Aaahhhh..... (too many martinis too)

[Adamphotoman]

I just read some 3 year old posts and I learned something. I can disassemble the Imagon from it's barrel and put it into an old Compur # 3 shutter. Now I have some more options.